Description
Self-winding movement with Co-Axial Escapement for greater precision, stability and durability. Free sprung-balance system with silicon balance-spring. Automatic winding in both directions to reduce winding time. Oscillating mass and balance bridge in 18 Ct red gold. Luxury finish with exclusive Geneva waves in arabesque.
Calibers based on the Omega 8521:
All watches using this caliber:

231.55.30.20.55.002 Omega Seamaster Aqua Terra 150M Co-Axial 30 Yellow Gold / Diamond / MOP / Bracelet

231.55.34.20.55.001 Omega Seamaster Aqua Terra 150M Co-Axial 34 Yellow Gold / Diamond / MOP / Bracelet

231.55.34.20.55.002 Omega Seamaster Aqua Terra 150M Co-Axial 34 Yellow Gold / Diamond / MOP / Bracelet

232.58.38.20.04.001 Omega Seamaster Planet Ocean 600M Co-Axial 37.5 Red Gold / Diamond / White / Alligator

123.55.27.20.55.003 Omega Constellation Co-Axial 27 Polished Red Gold / Waxing Moon Snow / MOP Supernova

231.55.34.20.55.003 Omega Seamaster Aqua Terra 150M Master Co-Axial 34 Sedna Gold / Diamond / MOP / Bracelet